I believe the key to stopping for a bit or even quitting gambling lies in the hands of the gambler himself. For start, most gamblers would benefit from playing less often and setting a gambling budget. I play twice a month - once in real casinos and once online - and that's enough for me.
But in the past, I used to play every time I had some money in my pocket, often playing until I had nothing or nearly nothing left.
Trying to hide from yourself behind different tools seems pointless to me.
Registering with places like Gamstop at that time would likely have worsened my situation rather than improved it. First, I would've felt like a complete loser. Secondly, I might have gotten my girlfriend to sign up for a casino account, leading to me losing money right in front of her, plus some potential problems on top of that.
Tools like bet blockers would've been useless for me too, making me feel like an absolute moron. They would've restricted my freedom to do what I want on the internet right in my own home. Even if that had happened, it wouldn't have stopped me if I wanted to play. I would still easily be playing on a Tesco phone like that Bonanza slot man below